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https://issues.apache.org/jira/browse/CALCITE-5740?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17731376#comment-17731376
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Rong Rong commented on CALCITE-5740:
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[~libenchao]
i dont have a generic mechanism in mind. but the idea is to detect whether the
access field is only from the LHS of the join
- for Aggregate there's {{RelOptUtil.getAllFields(aggregateNode)}} to detect
the all the bit access.
- for Project the original method in this class is
{{RelOptUtil.InputFinder.bits(projectNode.getProjects())}}, we can basically do
the same for aggregate
we can even create a util to detect all the inputField access bits for anyNode
but that would require some work (or maybe it already exists :-P )
but for now i dont know if there's any additional benefit for supporting other
nodes (maybe one more: CalcNode?) let me know what you think, should we (1) go
with generic and create a bit finder and change the rule to any RelNode, or (2)
add one for Aggregate only
> Support for AggToSemiJoinRule
> -----------------------------
>
> Key: CALCITE-5740
> URL: https://issues.apache.org/jira/browse/CALCITE-5740
> Project: Calcite
> Issue Type: New Feature
> Reporter: Rong Rong
> Priority: Major
>
> **Description**
> Currently we only have JoinToSemiJoin and ProjectToSemiJoin rule. which in
> the rule itself it performance check and see if the project accesses columns
> from the RHS result
> This can be extended to Aggregate as well, experimental code:
> https://github.com/walterddr/calcite/pull/1/files
> **Alternative**
> Alternative is to add a project/calc between the join and the aggregate to
> activate the project-to-semi-join rule. please share if there's any other
> alternative if I haven't considered.
> thanks
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